Adjustable gearing



Patented July 6, 1948 mesne, assignments, tmTheNoi-thern Pumpf GompanyeMnneapolis; Minni, acorporation of Minnesota.,

AipplicatinfMayl-S, 1944, SerialNo; 536,139`

intermesliingf lobes; orzvanes these: rotors; must A loe-.very .accurately positioned aso .amtoimeshsiprope erly; Ilheserotors; are carnied on parallelil shafts which.' have secured. thereto'. interrn'eshingi gears; onemi which; iszthe. driving gaan. 'Iegearsmust thus also'. bef tt'ed toimesh properly without :dise tur-bingithe proper.I meshing, ofthe?, rotorsand the proper: positioning` oith'e shaftsaforfthe rotors; It hasn been: one.` practice` to: secure the driving gear to its shaft and! then'- topositionI .thek other gear in proper meshing relation .andlftoipermanently secure Ait to-the-drivenrshaft as -byvaifeathe-red key. Whenthisis done-andthe customer or user ofthe pumpwishestofreplaceone'ofthe gears-ity is iinpossibletomake' anda send a gearf which can'be placed@ in: positionand will properly-l mesh: With theother gear;

It is an object' oil-:this invention t'oprovide a structureofl n'iountingfor'oneoii'said4 gears,` preferably' the drivenn gear; byz means` or which the gear-can'- be4 brougl'lt to proper meshingl relation;

It\'is'.f11rtheran object ofthe-invention; to pro'- vide a' gear` mounting toW be; usedv vvitl'rab pump having intermeshing' rotors bymnreansl of" which the drivngygears for; the. rot'orscan' be" easily brought. to` properl meshingA position'.

It is. another objectofthe invention to provide astructure of 'gear mounting inv which the por*- tion of the shaft` carryingA agearii's formed with a multiplicity ofcircumferentially spacedsplines, thegear-being bored; and grooved to t over said splines, which splines are of helical form together with means for-moving: the; gear longitudinally of said shaft to turn it somewhat circumferentially.

It is still further an object of' the invention to provide a gear mounting comprising ai shaft having its gear carrying portion-formed as a gear; the gear carriedby theshaf-t being'bored andfgr-ooved to fit-onV said gear, the teetlr of! one of saidt gears beingl helical;

These and otherobjectsandxadvantages of the invention will be fully set forth in the following description made inconnection Withtheacu companyingj drawings in^ which like reference characters referY to simiiar parts throughoutA the several views andirr which:-

Fig. 1 is a' horizontal' section; of a pump, said section beingi taken substantially on line I-I of "Fig, 2 ;l

Fig. 2 is a vertical section of said pump taken substantially on line 2 2 of Fig. 1;

Fig. 3 is a partial View in horizontal section shown on an enlarged scale; and

Referring' tortheV drawings,l apumprI is shown comprising a: frame designated gener-ally.' as t0;

. said frame being provided with`V a casing portion ma. in: which is` formed' the; rotor: chamber- Ulli.y Said .casing has an. upwardly extendinge portion Ic. through. which extends a discharge passage Iiidi Casing'lilihasacbase portion Iiieiaboyeiwhich is fformed' an inlet-'portionlily?z having ther-pas sages my extending therethrough. communicating. withz passage lhnwhich leads to.v4 thev .rotor chamber. IIlb.` Portions IIlJf' are constructed with flanges lili; to; which can be secured thegnecesxsary connections to: the; p11-mrt. Said pump com prises a pair of.g rotors l II and; I2? shown? asfhaving af pluralityoft lobes or vanes` Illa andkla respectivelm. While the?. number; offsaid' lobes-.couldfbe varied; in the vernbodirrrentofthe invent-ioni illus-.- tratedtheyare shown.asithreefinnumber:` Rotors ILIf and: lzare securedl to.: shafts: I3@ and. Iifll respectively inany: suitablef manner' as by'thelkeyfs |35: The shafts I3 and: Ik are journa-liedainzbear; ings l' I6?I atv each;V endfofi'the rotors I'I7 and I2 which bearings: arercarried in frame Vportions4 Ifgi-i and Ilc, Y Said: bearingsy IliaI at: oneV end-are shown asL connected" tov frame; portion: lillef by; headed bolts I"I.. Shaft Is3 is providedr with: threads.- at the: outer or: remote-f sides'. of" bearings" In and nuts Isf are: threaded: thereon.; the-same being shown' as: having locking: Washers.; I 9:'. adiace-nt the-retor.. An end. portion Hlm-z of the,l freine-- is bolted.` to` porti'onz` IIlk by the circumierentially spacedf screws` on'bolts: 20:. Portiona` IfilwotA the frame. isA boltedf'tm portion;l I'Ily: bythe;A cincume ferentiallyelspased bolts: orf screws.' 2;I-"and' the portion; Iuf byf: the circuniierentially.,` spaced headed: andifnnttedebolts; 22 i passirrgfthroughx; peripheral flanges oniportions; tim and IIIo.. Shaft I3? is: the drivingfzshaft-f and; thef samez extends tlirough'ftheY fron-tf, wall-ofthe, pump; for-medi by portioni Iii@ andi. is f packed@ byipackingr-Zg held? Yin ai packing recess'ini portion` IlIlULsurroun'ding shat I3 said?" l packing beingfcompressed by:- a packing gland 2M. Alcoupling: ZE connects;shaftA I ter a main drivingf shaft Z'ifwhich Willz be; connectedfgto a suitable motor. Within the. portion. lum sha-tt I3flhas:securedthereto-af spurgeanwii vSpur gear 3Il'f isfsecuredf 19o-a reduced? portion of.' shaft: |371 by a keyJ 3 I Shaft I 3f is; thre adedi 'at the outenside off gearf 30mn-d provi-ded? with ai nut itf'or' hold ing vgear 301secureiy'in position;` Alocliingiwaslier Zfis' di'sposedf'betweenfgearfSandi-nnt Shaft I4'L adjacent the front bearing` Iihasf a reduced portion on which'is 'tteda collar 33T, whichicoll'ar abuts bearing I6 at one side.` Thefportioni Ma of 'shaft I'41whichcarries collar: 33 also carries the driven gear 34. Said portion Illa is formed as a gear having a multiplicity of teeth I4c preferably of involute form and as shown in Fig. 3,

3 these teeth extend atan angle to the axis of shaft I4 and thus in inclined or helical form. Shaft I4 has 'a reduced threaded portion I4b at the outer side of gear 34 and a nut 35 is threaded on portion I 4b and is provided with a locking washer Washer 3E like washers I9, has projecting 36. tongues 36a adapted to be bent substantially at a right angle and disposed in circumferentially spaced grooves 35a in shaft 35. Gear 34v is' thus held against collar 33 or againstv one or vmore shims 31.

In operation when the deviceis assembled the rotors Il and I2 will first be tted to mesh properly and gear 3B will be secured to shaft I3. It is then necessary to have gear 34 properly mesh with gear 30 while maintaining the proper circumferential relation of shafts I3 and I4 and the rotors. The gear 34 can be placed on shaft portion I 4a with one of the grooves inits bore ntting over a particular tooth Mc on then gear formed on portion I4a. If the gear 34 is notthen in proper position it can be shifted so that said groove will be placed on the next tooth |40. This will bring gear 34 to a dierent circumferential position. The actual amount of difference in theposition ofa tooth on gear 34 will be small. The number of teeth on gear 34 will be somewhat near the 'number of teeth on gear I4c. The ideal condition would be'to have a difference of one tooth on gear'34 and the gear comprising teeth I4c.- There would then be a very large number of `different circumferential positions in which gear 34 could be placed. If gear 34 is brought almost to proper position by shifting it on 'the teeth I4c it can be further moved slightly by moving it to different positions longitudinally of shaft portion `I4a. This can be done by rotation of -nut 35. Owing to'the inclined form of the-teeth 14e it will be seen that any movement of gear 34`longitudinally of shaft I4 will result in some slight rotationrof said gear or in bringing it to a different circumferential position. It `may be necessary to place one or more shims 31 between'gear 34and collar 33A in order to properly locate said gear.` Itv will thus be seen that gear lEli-can be brought to proper position by Vvery fine` adjustments. When properly positioned it will be locked in position by nut 35. With gear 34 so held it will be very easy to replace said gear and again bring the replacing gear' to the proper position.

' From the above description it will be seen that I have provided a pump structure and structure of gear' mounting by means of which a gear can be brought to a proper position by very fine adjustments. The invention constitutes a great improvement in the pump and as above stated, renders it possible to supply additional repair gears after the pump has left the factory. A very ingenious gear mounting has also been produced. The invention has been actuallyr reduced to practice, found to be very successful and efiioient and isbeing commercially made.

It will, of course, be understood -that various changes maybe made inthe form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out'the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is: v

1. rA structure of the class described having in Y Ldriving gear fixed to one of said shafts, a second gear meshing with said driving gear and mounted on the other of said shafts, one of said shafts having a multiplicity of splines formed thereon,

, said splines extending somewhat helically of said I f shaft and said gear on said shaft having grooves tting'over' said splines, said splines being close in number to the number of teeth on said second gear whereby a, gear can replace said gear and be brought into proper meshing relation with the other gear without disturbing the circumferential relation of said shafts. 1

2. A structure of the class described having in combination, a pair of parallel shafts, cooperating means on said shafts determining the circumferential relative positions of said shafts, a driving gear fixed to one of said shafts, a second gear meshing with said driving gear and mounted on the other of said shafts, said latter shaft 'having a multiplicity of splines formed thereon, said splines extending somewhat helicallyl of said shaft and said second gear having-grooves fitting over said splines, said splines being closein number to the number of teeth on said second gear, means on said shaft for moving said'second gear longitudinally thereof, and means engaging said second gear for determining its position longitudinally of said shaft. I

3. A structure of the class described having in combination, a pair of parallel shafts, cooperating means on said shafts determining the circumferential relative positions of said shafts, a driving gear fixed to one of said shafts, a, second gear meshing with said driving gear and mounted on the other ofl `said shafts, one of said shafts having a. multiplicity of splines formed thereon, said splines extending somewhat helically of said shaft and the gear on said shaft having grooves fitting over said splines, said splines being yclose in number to the number of teeth on said latter gear, means on said shaft forming an abutment adjacent said latter gear, a nut threaded on said shaft at the other side of said latter gear, and means of variable. thickness disposed between said abutment and said latter gear whereby the position of said latter gear longitudinally of said shaft may be determined Aand fixed.

JOHN T. G ONDEK.

' REFERENCES CITED n The following references are of record in the file of this patent:

- `UNITED STATES PATENTS Number Name Date 898,779 Plank 1 Sept. 15, 1908 999,634 Despaigne Aug. 1, 1911 1,787,717 Boulet 1 Jan. 6, 1931 FOREIGN PATENTS OTHER REFERENCES Sel, N0. 321,834, A. P. C. publication, May 25,

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